Please use this identifier to cite or link to this item:
http://hdl.handle.net/2122/4054
DC Field | Value | Language |
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dc.contributor.authorall | Solarino, S.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione CNT, Roma, Italia | en |
dc.contributor.authorall | Eva, C.; Dipartimento per lo Studio del Territorio e delle sue Risorse (DipTeRis), Università degli Studi di Genova, Italy | en |
dc.date.accessioned | 2008-09-12T08:11:33Z | en |
dc.date.available | 2008-09-12T08:11:33Z | en |
dc.date.issued | 2007-10 | en |
dc.identifier.uri | http://hdl.handle.net/2122/4054 | en |
dc.description.abstract | Aim of this paper is to discuss on the T phases generated after the mb 6.5 earthquake that shook Algeria on May 21, 2003. The seismograms, recorded by a cluster of seismic stations located on the coast facing the Ligurian Sea, Northern Italy, some 800 km N-NE from the source, represent a good database able to shed some light on the recognition, propagation and characteristics of these quite uncommon phases. The occurrence and the recording of T phases are in fact due to particular conditions, and require both particular characteristics of the bathymetric slope and the existence of a clear path between the instruments and the earthquake’s source: these constraints are exactly realized in the north-western part of the Mediterranean Sea, whose coasts have been affected several times in the past by similar events. The preliminary investigations on the complex recorded seismogram show two different behaviours for stations close the coast and inland. In both cases, two distinct T phases (namely T1 and T2) are observed. In one case they have apparent velocities close to an average SOFAR channel, and are thus the recording of direct T phases. In particular, T1 is probably a precursor due to some scattering, while T2 is the direct T wave. Conversely, the recordings of the stations inland show apparent velocities that suggest back conversion of the original T to P and S waves and a crustal path. The frequency content of the T phases, as derived from the spectral analysis, reveals marked amplitude peaks also in the range 1-3 Hz, conversely to what was proposed by other authors for similar occurrences in other parts of the world. Since the geometry and shape of the SOFAR channel vary, it is highly likely that the spectrum is biased by the water conditions and the frequency content might change in different seas. Finally, the attenuation of the T phase does not depend on the actual distance of the receiver from the source but rather from the backconversion point: the amplitude varies thus with the in-land path and decreases proportionally to x−1. | en |
dc.language.iso | English | en |
dc.relation.ispartof | Annals of Geophysics | en |
dc.relation.ispartofseries | 5/50 (2007) | en |
dc.subject | T waves | en |
dc.subject | Ligurian Sea | en |
dc.subject | SOFAR | en |
dc.subject | frequency content | en |
dc.title | T waves in Western Mediterranean Sea after the May 21, 2003 Algerian earthquake | en |
dc.type | article | en |
dc.type.QualityControl | Peer-reviewed | en |
dc.subject.INGV | 04. Solid Earth::04.06. Seismology::04.06.09. Waves and wave analysis | en |
dc.relation.references | JENSEN, F.B.,W.A. KUPERMAN, M.B. PORTER and H. SCHMIDT (1994): Computational Ocean Acoustics (Am. Inst. Phys. Press, New York), pp. 612. KOYANAGI, S., K. AKI, N. BISWAS and K. MAYEDA (1995): Inferred attenuation from site effect-corrected T phases recorded on the Island of Hawaii, Pure Appl. Geophys., 144, 1-17. NEWMAN, A.V. and E.A. OKAL (1998): Teleseismic estimates of radiated seismic energy: the E/M0 discriminant for tsunami earthquakes, J. Geophys. Res., 103, 26885-26898. OKAL, E. (2001): Converted T phases recorded on Hawaii from Polynesian nuclear tests: a preliminary report, Pure Appl. Geophys., 158 (3), 457-474. OKAL, E. and J. TALANDIER (1997): T waves from the great Bolivian deep earthquake in relation to channeling of Swave energy up to the slab, J. Geophys. Res., 102 (B12), 27412-27437. OKAL, E., P.J. ALASSET, O. HYVERNAUD and F. SCHINDELE (2003): The deficient T waves of tsunami earthquakes, Geophys. J. Int., 152, 416-432. TALANDIER, J. and E. OKAL (1979): Human perception of T waves: the June 22, 1977 Tonga earthquake felt on Tahiti, Bull. Seismol. Soc. Am., 69 (5), 1475-1486. TALANDIER, J. and E. OKAL (1998): On the mechanism of conversion of seismic waves to and from T waves in the vicinity of island shores, Bull. Seismol. Soc. Am., 88 (2), 621-632. | en |
dc.description.journalType | JCR Journal | en |
dc.description.fulltext | open | en |
dc.contributor.author | Solarino, S. | en |
dc.contributor.author | Eva, C. | en |
dc.contributor.department | Istituto Nazionale di Geofisica e Vulcanologia (INGV), Sezione ONT, Roma, Italia | en |
dc.contributor.department | Dipartimento per lo Studio del Territorio e delle sue Risorse (DipTeRis), Università degli Studi di Genova, Italy | en |
item.openairetype | article | - |
item.cerifentitytype | Publications | - |
item.languageiso639-1 | en | - |
item.grantfulltext | open | - |
item.openairecristype | http://purl.org/coar/resource_type/c_18cf | - |
item.fulltext | With Fulltext | - |
crisitem.author.dept | Istituto Nazionale di Geofisica e Vulcanologia (INGV), Sezione ONT, Roma, Italia | - |
crisitem.author.dept | DipTeRis Dipartimento per lo studio del territorio e delle sue risorse, Università di Genova | - |
crisitem.author.orcid | 0000-0002-9577-1347 | - |
crisitem.author.parentorg | Istituto Nazionale di Geofisica e Vulcanologia | - |
crisitem.classification.parent | 04. Solid Earth | - |
crisitem.department.parentorg | Istituto Nazionale di Geofisica e Vulcanologia | - |
Appears in Collections: | Annals of Geophysics |
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